In the field of therapy of hypertension, angiotensin II (All) receptor antagonist (AIIA) has attracted attention as an effective agent for the therapy of hypertension following angiotensin I converting enzyme (ACE) inhibitors. A compound of the formula (I), for example, benzimidazole-7-carboxylic acid and derivatives thereof having a strong anti-AII action (cf. EP Publication No.-0425921 A1 official gazette and EP Publication No. 0459136 A1 official gazette) are considered to have, for example, the following advantages as compared with ACE inhibitors.
1) It has been known that there are a series capable of producing AII, which are not in the series of ACE. For example, benzimidazole-7-carboxylic acid and derivatives thereof also inhibit the action of this AII which is not dependent on ACE, and therefore it may well be that these compounds exhibit a stronger and more effective hypotensive action than that of ACE inhibitors. PA0 2) Since benzimidazole-7-carboxylic acid and derivatives thereof do not enhance the action of bradykinin observed in ACE inhibitors, they are less likely to cause coughing as a side effect. PA0 (1) a pharmaceutical composition for oral use comprising an effective amount of a compound of the formula (I) having antagonistic action to angiotensin II ##STR3## (wherein the ring W is an optionally substituted N-containing heterocyclic residue; R.sup.3 is a group capable of forming an anion or a group convertible thereinto; X is a direct bond or a spacer having an atomic length of two or less between the phenylene group and the phenyl group; and n is an integer of 1 or 2) and an oily substance having a lower melting point, and PA0 (2) a further object of the present invention is to provide a method for preparing a stabilized pharmaceutical composition for oral use comprising an effective amount of a compound of the formula (I) having antagonistic action to angiotensin II ##STR4## (wherein the ring W is an optionally substituted N-containing heterocyclic residue; R.sup.3 is a group capable of forming an anion or a group convertible thereinto; X is a direct bond or a spacer having an atomic length of two or less between the phenylene group and the phenyl group; and n is an integer of 1 or 2) and an oily substance having a lower melting point, which comprises admixing the compound of the formula (I) with an oily substance having a lower melting point and then subjecting the mixture to molding.